Electrode structure for multigrid electron discharge tubes



y 1948- J. L. H. JONKER 2,444,740

' ELECTRODE STRUCTURE FOR MULTIGRID ELECTRON DISCHARGE TUBES Filed July 20, 1946 INVENTO R JOHA/V ZODfW/JK HWDR/XJOA BY%W% v successive grids are located. Such templets may grid 2 are located in the deep notches and those Patented Jul 6, 1948 v r 1 .Y-UINITED" STATES PATENT ELECTRODE STRUCTUREFOR MULTI GRID ELECTRON DISCHARGE TUBES Johan Lodewijk Hendrik Jonker. Eindhoven,

Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Comm, trustee Application July 20, 194 Serial No. 685,156

In the Netherlands September 10, 1943 Section 1, Public Law 690,August 8, 1946 Patent expires September 10, 1963 3 Claims. (01. 2502'7.5)

This invention relates to electric discharge alternatelycomprises deep and shallow notches tubes comprising a plurality of grids, and more in which the wires of the successive grids are particularly to the fixation of the wire-s of at least wound, i. e., the wires of the inner grid in the deep two successive grids with respect to each other. notches and those of the following grid in the In many cases it is advantageous that the wires 5 shallow ones. By means of an inclined position of successive grids should be exactly fixed with of the deep notches it may be ensured that the respect to one another. This involves difficulties bottom of these notches lies exactly under that in particular when the grids are arranged close of the shallow notches, so that the wires of the behind one another, since in this case a small two grids are located behind each other. The deviation in the position of the grid wires implies form pieces may be fixed in the insulating centrea comparatively great variation in the distance ing plates of the electrode system or in another between the two grids. In the case of such grids manner. arranged close behind one another the fixation In order that the invention may be clearly of the grid wires is very difiicult, however, the understood and readily carried into eflect, it will more so as with mutual distances of the order of be described more fully with reference to the magnitude of, say, 0.3 mm. the use of very thin accompanying drawing.

grid wires is required. Since such wires exhibit Fig. 1 is a cross-sectional view,

a small mechanical rigidity, the above-mentioned Fig. 2 shows a detail of a. form of construction drawback will occur to a greater extent. Conseaccording to the invention.

quently, one would have to proceed to utilizing Fig. 3 is a cross-sectional View, and

a plurality of supporting bars per grid, but in this Fig. 4 is a detail of another form of construccase there arises a drawback that, due to the tion according to the invention.

small spacing, the supporting rods, which would In Fig. 1, reference 1 indicates the cathode,

be arranged in the vicinity of the active grid parts, 2, 3 and ti grids, 5 an anode. The grid-s 2, 3 and 4 would likewise have to be very thin, so that their are wound on supporting rods 6. The wires of rigidity is small. It is known, indeed, to provide the grids 2 and 3 are exactly positioned with revery thin cross rods supported completely by the spect to each other and are fixed in this position grid wires, but these rods can serve only for the by templets l of insulating material, for example,

relative fixation of the Wires of one grid and not of steatite, magnesium oxide, mica, or similar mafor the relative fixation of wires of successive terial. These templets may be shaped in the form grids. shown in Fig. 2. It is evident that more grids According to the invention, the said drawbacks may be present and that the wires of more than are obviated by that in an electric discharge tube two grids may be relatively fixed in the said comprising an electrode system having a plurality manner. of grids the grid wires of at least two successive Fig. 3 shows a tube containing four grids in grids are relatively fixed by means of templets which, as before, the grid wires of grids 2 and 3 of insulating material, comprising notches in must be relatively fixed. This is ensured in this which bear the grid wires of the said successive case by means of strip-shaped members 8 altergrids. nately comprising at one longitudinal side a. cer- The templets may have the shape of narrow tain number :of shallow and deep notches 9 and strips comprising at one or at each longitudinal l0 respectively. The grids 2 and 3 are wound on side cavities or notches in which the wires of the these members in such manner that the wires of be arranged in a simple manner between the grids of grid 3 in the shallow notches 9. By means of by that the supporting rods of the outer of the an inclined position of the deep notches Ill, it may two grids are slightly pressed towards each other, be ensured that the wires 2 and 3 are located bedue to which the wires of this grid take a somehind each other. The spacing of 2 and 3 may be what convexer form, so that the strips can be very small. The members 8 may be fixed in the pushed between the two grids. After releasing centreing plates at the extremities of the electhe supporting rods, the templets are clamped trode system. It is, however, also possible to probetween the grid wires. vide the grids 2 and 3 with ordinary supporting Further, it is possible to wind the grids on the rods 6 which in this case may be arranged in the templets themselves, so that they also constitute plane of the other rods 6. the supporting rods for the grids. To this end, Although only two forms of construction are the templets at one of their longitudinal sides shown it is evident that according to the invention templets of different shape can also be used. being located in a line normal to said longitudinal What I claim is: side to fix said grids one behind the other. 1. An'zelectrodeistructure for a rmdltigrid elem 3 3.1Anelectrbde structure lfor a multigrid electron discharge'tube'having a pluralitypf'grids tron" discharge tube having two grids mounted mounted one behind the other, comprising a plu- 5 one behind the other on a line normal to a source rality of grid supports and a plurality of grid of electrons, comprising a cathode element, a elements on said grid supports; eachrof said'supplurality ot grid supports, a plurality of grid eleports comprising an insulating mmberiihavinga j mentstonrsaid grid supports to form said grids, plurality of notches spaced along asingle longiand means to position said supports with said tudinal side thereof, said notchesbeing positioned lo -gridssurrounding1said cathode element, each of in successive groupings anasuceessive notches bf -DD T T com sin an insulating member said groupings being of successively vary having plurali y iO notches at an an and depths, the innermost extremities of said notches spaced along a single lon d l Side h reof, of each of said groupings being-located or'r a line said riotchesabein pOSitiOXled in pairs and One normal to said longitudinal sidepfsazid-insulating1'5"- 0tBhof-ea'oh of said pairs being deeper than the member to fix the position of said grid elements. --0therto!1ocate the innermost extremities of the 2. An electrode structure for amultigrid}e1ecv-riotches bf-each of said pairs in a line normal to tron discharge tube having the successive grids said cathode element. thereof mounted with the grid adjacent'theelem tron discharge means shadowing the successive 29 JOHAN LODEWIJK HENDRIX JONKER. grids -therefrom,: ecirnprising-- a-=-p1urality fof grid siipporting hienibers and a pliirality of gridwires E C CITED longsfildimembrsilalbhiof=S9Jidmember5hwmpi'is- Ihe' following references are of 4 record. in :the mg an onsul'ating -member having ree'ritrant por- K1319 i t ip'a tent:

tionsspaced -along a single longitudinal-"side 25 there'of; said reentrant-portions' being positioned "UNITED STATES PATENTS on -successivegroupings and-being 0f f successively Number 1 Name Date -'varying depthsg thefihnertmost'extremities-ofsaid Rei'21y1'53 -1 Hazeltine =July 18, "1939 -reehtrant 'portionsbi each of said groupings 2,172,750 aI-Iaze'ltine -'Sept". 12, 1939 

